No. 374.] REVIEWS OF RECENT LITERATURE. 125 
theory, the transformation of staminate into pistillate flowers occurs 
under conditions disadvantageous for the development of the vegeta: 
tive apparatus. 
Plankton Studies. — The first article of volume five of the Bulletin 
of the Lilinois State Laboratory of Natural History, recently published,! 
contains a bibliography of the methods of conducting plankton studies 
and a useful description of the oblique haul and pumping methods 
which have been in successful use for some years at the Biological 
Station at Havana, Ill., in the collection and separation of the minute 
animals and plants floating free in the water and incapable of materi- 
ally changing their position by their own efforts. 
Students of this rather new phase of biology will also find an in- 
teresting preliminary report on the plankton of some of the lakes of 
the Alps and Jura” in the Buletin of the Botanical Laboratory of 
the University of Geneva for June, 1897. T 
ZOOLOGY. 
Cell Lineage. — In a paper entitled “Considerations on Cell 
Lineage, Based on a Reëxamination of Some Points on the Develop- 
ment of Annelids and Polyclades,”*® Prof. E. B. Wilson presented 
observations regarding the origin and relations of the mesoblast in 
annelids and polyclades which illustrate the fact of ancestral remi- 
niscence in cell lineage. In some of the annelids (Aricia, Spio, 
Nereis, and others) the primary mesoblasts have not been properly 
so called, for before giving rise to the mesoblast bands they bud forth 
cells that may be, in some cases, traced into the wall of the archen- 
teron. In Nereis not less than six or eight such cells are formed ; 
these become pigmented, wander into the interior, and finally give 
rise to the posterior part of the archenteron. In Aricia and Spio 
only a single pair of corresponding cells is formed, and they are so 
small as to play a quite insignificant part in the building of the body. 
A comparison of these results with those of Conklin on Crepidula 
1 Kofoid, Plankton Studies, I. Methods and apparatus in use in plankton 
investigations at the Biological Experiment Station of the University of Illinois. 
2 Pitard, Quelques notes sur la florule pélagique de diverses lacs des Alps et 
du Jura. 
3 Read before the New York Academy of Sciences, Biological Section, Dec. 
13, 1897. 
